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So I normally race a STS prepped CRX, but last week it's engine popped. So today we raced my wife's STI. We had some serious issues with wheel spin and a weird jerky/vibration/bouncing. First off here is the car's setup:

The issue is on corner exit under power it feels almost like the clutch is slipping, and sometimes the car jerks or even 'bucks'. So far from searching it sounds like my car may be lifting an inside rear wheel and all the power is spinning air...

1. Is this a common issue? Stock STI's spinning an inside rear tire with just a big rear swaybar?

2. Could my rear camber be making the problem worse? I would think that if the inside rear tire was getting light that much camber would make for a really small contact patch...

Any other ideas on what's wrong? Or how to fix this besides putting the stock rear bar back on?

i've never experienced that when i was autoxing my 04 sti with rce yellows or jdm pinks, 255s, and the same WL rear bar set to full stiff so i don't understand how the inside rear wheel would lift with stock springs.

i've never experienced that when i was autoxing my 04 sti with rce yellows or jdm pinks, 255s, and the same WL rear bar set to full stiff so i don't understand how the inside rear wheel would lift with stock springs.

Subarus tend to pick up rear wheels when they are stiff or softly sprung. Some stiffen the front (given they already have stiff C/Os) to help keep the wheel down, but I've found the car looses steady state grip, and therefore speed, given how much rate is in the front vs. rear (stiff front bar + heavier springs in front vs. rear) of the car. That being said I tend to run more rate in the rear than the front.

With any of my STi's, '05 or '06, none of them have clunked or bounced funny exiting corners under power with any of the setups I have tried. From the pictures below you can see I have a bit of experience three wheeling on street tires.

From what you have described, I would personally be looking for mechanical issues. Broken mounts, diff problems, etc. It's possible you are seeing what the BSP or SM STis are seeing when they have tons of grip!? Seems unlikely though.

A less scatter brained post than I had above. Being home sick has some time advantages.

The suspected problem of rear wheel lift at corner exit may be difficult to actually happen. Generally rear wheel lift for GC/GD Subarus happens on corner entry under braking. At that point your weight transfer is heavily set to the outside front wheel, taking weight off the rear. As the car settles into the corner the weight transfer front to rear balances a little more while running maintenance throttle. The rear wheel sets back down in steady state. On corner exit the steering wheel is being unwound while adding throttle (early throttle in the AWD car ) and the weight starts shifting to the rear of the car. With weight transfer to the rear it's very difficult to pick up a rear wheel. Generally it's a front inside wheel that can lift on corner exit. BMWs are well known for lifting front wheels on corner exit. See the sequence of corner shots below.

It is possible you may be spinning an inside wheel on corner exit, except for the fact there is tons of droop travel on the stock shocks. It is possible however. If spinning an inside front wheel is happening on corner exit, more rear spring rate would be in order or the ability to add rear compression or front rebound (not something you can do). I would look for broken mounts, diff issues, or the like first.

As a side note, adding a front bar to your softer camber lacking setup should help with front grip. My '05 STi ran JDM pinks with 24mm whitelines bars on full stiff all around. Great balance if not a touch loose ~-1F/-1.7R for camber and zero toe. It's probably not the rear camber causing your issue.